So far none of the guides have worked at all. The typical LE source from github where you use ‘letsencrypt-auto certonly’ is incapable of recognizing that OS. Although, I did initially run that on 5.8 and was able to get a cert on OpenBSD during testing over 6 months ago.

Instead, it is now recommended to use the -current branch of 6.0 (which I am not), or use acme-client. acme-client is incapable of working as well: